Differential Diagnosis

The patient's symptoms of difficulty with head turning, increased reflexes in the right upper extremity, and abnormal repetitive movement of the right upper extremity on head turning, despite normal cervical and brain imaging, suggest a neurological condition. Here's a categorized differential diagnosis:

• Single most likely diagnosis
  • Hemiplegic Dystonia: This condition is characterized by involuntary, repetitive movements on one side of the body, often associated with hemiplegia (weakness on one side of the body). The abnormal movements can be triggered by specific actions, such as head turning. Increased reflexes in the affected limb further support this diagnosis.
• Other Likely diagnoses
  • Cervical Dystonia: Although cervical imaging is normal, dystonic movements can be localized to the neck or involve the upper limb, especially with head turning. The increased reflexes might not be directly related to the dystonia but could indicate a separate issue or a more widespread neurological condition.
  • Hemiparkinsonism: This condition involves Parkinson's disease symptoms (such as rigidity, bradykinesia, and tremor) on one side of the body. While less likely given the specific symptoms, it could explain the increased reflexes and abnormal movements, especially if the patient has a form of parkinsonism that presents with dystonic features.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Stroke or Transient Ischemic Attack (TIA): Despite normal brain imaging, it's crucial to consider vascular events, especially if the symptoms are of acute onset. Some strokes or TIAs might not show immediate changes on imaging, and the clinical presentation can sometimes be atypical.
  • Multiple Sclerosis: This demyelinating disease can present with a wide range of neurological symptoms, including increased reflexes and abnormal movements. Although less common, it's a diagnosis that should not be missed due to its significant implications for treatment and prognosis.
• Rare diagnoses
  • Rasmussen's Encephalitis: A rare inflammatory neurological disease, characterized by seizures, hemiparesis, and eventual brain atrophy. The presence of abnormal movements and increased reflexes, particularly if progressive, might suggest this diagnosis, although it is quite rare.
  • Wilson's Disease: A genetic disorder leading to copper accumulation in the brain and liver. Neurological symptoms can include dystonia, tremors, and rigidity. Although rare, it's an important consideration in young patients with movement disorders and should be ruled out with appropriate testing.